Combined manual and speed responsive gas turbine control system



Dec. 1, 1953 H c g- 2,661,429

COMBINED MANUAL AND SPEED RESPONSIVE GAS TURBINE CONTROL SYSTEM Filed- July 13, 1951 Q/vwAAAXZo/L Mama 5. ewvdwx Patented Dec. 1, 1953 COMBINED MANUAL AND SPEED RESPON- SIVE GAS TURBENE CONTROL SYSTEM Harold. E. Reichert, New Berlin, Wis, assignor to Allis-Chalmers Manufacturing Company, Milwaukee, Wis.

Application July 13, 1951, Serial No. 236,544

7 Claims. 1

This invention relates in general to control systems and in particular to control systems for the combustion chambers of gas turbines.

Where a gas turbine is utilized to drive an electric generator for supplying current to a load, such as a traction motor, it is customary to vary the fuel supplied to the turbine combustion chamber and to vary the excitation of the generator to vary the speed and loading of the turbine. In some of such systems a manually operable throttle is utilized to control the iiow of fuel to the combustion chamber, and an adjustable governor having a speed setting determined by the throttle setting and responsive to the turbine speed is utilized to control the excitation of the generator. In such systems, it is possible that for a given speed setting of the governor, the governor will be unable to adjust the excitation of the generator to sufiiciently load the turbine to maintain the turbine speed at the desired value, with the result that the turbine will overspeed and possibly damage the installation before the overspeed mechanism of the governor shuts the turbine down To prevent such an occurrence, it

is desirable to correlate the governor and the throttle so that, although the governor adjusts the excitation and the throttle controls the fuel during normal operation, the governor is operative to reduce the fuel to reduce the turbine speed it the governor is unable to maintain the set speed by adjustment of the generator excitation.

It is therefore an object of this invention to provide an improved control system for a combustion chamber supplying motive gas to a gas turbine.

It is additional object of the present invention to provide control system for a combustion chamber supplying motive gas to a gas turbine driving an electric generator, in which system an adjustable governor normally operative to adjust the excitation of the generator is operative to control the fuel supplied to the combustion chamber to prevent the turbine from overspeeding.

it is further object of this invention to proa control system for a combustion chamber suppiying motive gas to a gas turbine, in which system the position of the turbine throttle limits the fuel supplied to the combustion chamber independently of the action of the turbine governor.

Objects and advantages other than those set forth above will be apparent from the following descrip (on when read in connection with the accompanying drawing, the single figure of which diagrammatically illustrates the circuits and apparatus of one embodiment of this invention.

Referrin to the drawing by character of reference, numeral denotes a gas turbine supplied with motive gas from a combustion chamber 1. Chamber i is supplied with compressed combustion air through a pipe 8 from a compressor 9 driven by turbine (5 through a shaft ll. Turbine 3 may be utilized to drive any suitable load, such as direct current generator l2 connected to shaft ii either directly or through suitable reduction gearing. enerator 52 has an armature lid and a field winding 52b. Armature Eta supplies current to any suitable electrical load, and if the turbine is utilized to drive a locomotive, such load may comprise the armature 53a of a traction motor is having a series field winding 13b. Armature 82a is connected to armature I300 and field winding l3b through the contacts lilo of a solenoid relay Ell having a contact bridging member 15b and an operating coil Ella. It will be understood that although only one main generator and one traction motor have been illustrated, additional machines may be provided if required to produce additional traction power.

Field winding l2b of generator 42 is supplied with current from any suitable controllable direct current source, such as the armature El a of an amplifying exciter ii having a self-exciting field winding ill) and, a control field Winding llc. Field winding lib is connected across armature l to in series with an adjustable resistor 18, while field winding He is connected in series with a battery it and adjustable resistance means in the form of adjustable resistors 2 l, 22.

Combustion chamber 3 is provided with a fuel burner 23 to which fuel is supplied from a fuel regulating valve 2%. Valve 25 is of a conventional type in which the fiOVV of the fuel through the valve from a pipe connected to a fuel source is controlled by a variable control pressure impressed on a valve actuator 2t from a pipe 25. The greater the pressure in pipe 253, the greater is the opening of valve it to increase the how of fuel to burner 23. Pipe 26 is connected to the output chamber 35a of fluid pressure controlled valve ill, herein referred to as a fuel totalizer. The totalizer is provided with flexible diaphragms, such as diaphragms iii, Sly which, together with adjacent rigid partitions, such as partitions elk, Elle, for input chambers 35b,

lb which are adapted Sic, .ilcl, tie, 3H, Big and to receive fluid input control pressures for controlling the output pressure in chamber cm.

The diaphragms are connected together to a movable rod Blm which is moved in response to variations in the algebraic sum oi": the the input output pressures acting on the totalizer. During part of its stroke, rod 3lm cooperates with a valve stem am, which is then fixed, to variably open an exhaust port illr. During the remainder of its stroke, rod Elm actuates valve stem em to control a supply port 31p. When stem am is moved to the right by rod 31m, the stem closes exhaust port 3h and opens supply port tip admitting air to chamber am ,from a pipe 32 connected to a suitable source of air under pressure, such as a reservoir 33. When connecting rod film is moved sumc ientl-y to the left, valve stem tin closes supply port tip and opens exhaust port 5H1 to allow air from chamber 3m to escape to atmosphere through a chamber provided in rod Ellm and in partition 3H0. In an intermediate position, rod Elm maintains both ports sip, Slr closed. Thus, totalizer 3| acts to add or subtract the pressures in "the totalizer input and output chambers to control the output pressure, with movement of rod 3 I'm to the right causing air to be admitted to chamber 31a until the pressure therein increases to a value balancing the algebraic sum or the pressures on the diaphragms, and movement of rod 31m to the left causing a reduction in pressure in chamber 31a until the pressures are again balanced on the diaphragnis. A loading spring 3h) may be utiline to put an initial bias or loading pressure in chamber cm.

Input chamber 31s of totalizer ti receives a control input pressure through a pipe 2'! from the output chamber 28a of a thermostatic pressure sending valve 28. Chamber 28a is connected through pipe 32 to reservoir 33 and has an escape orifice 230 to permit chamber 28a to slowly vent to atmosphere. Valve 23 has a bimetallic element 2812 which is secured to the valve housing and which is adapted to vary the position of a valve member 28d separating cham ber Zi a from pipe 32. Bimetallic element 2% is subjected to the temperature of the turbine motive gas at a predetermined point in the turbine, preferably the inlet end thereof. A spring 28) exerts a predetermined biasing force against bimetallic element 281) to maintain valve member 23d closed until the temperature of the tur bine motive gas reached a predetermined value. A needle valve 29 and a volume tank 38 are preferably connected in pipe 21 to delay the transmission of pressure changes from chamber 28a to chamber the.

Input chambers 3 lb, 3 lo have impressed thereon throng pipe 35 and a pipe Ml input pressures from the output chamber 34a of a governor repeater totaliaer 34 similar to totalizer 3|. This input pressure to chamber illb is applied directly from pipe lt, while chamber 310 is connected to pipe All through a needle valve or restricting orifice 36 and a volume tank 3'! to delay the transmission of changes in pressure in pipe 4a to chamber Zllc. Supply port 34): is con- .n eted to reservoir 33 through a pipe 38 joining determined output pressure in pipe tively, to vary the setting or the governor.

When turbine l3 running at the desired speed,

pistons Alb, tic iuncover approximately one-hali of ports 4th, to, respectively, to produce a pre- When turbine t is running above the desir-d speed, nyball mechanism M pulls pistons 11b, tie down to reduce the open area of port tilt and to increase the open area of port iii "to thereby roduce the output pressure to has When turbine i5 is running considerably ovcrspeed, piston 42b completely closes port and piston Mo completely port Hi to reduce the governor output pressure to zero. On underspeed condi tions, the pistons l lb, '4 is move upward to there by increase the output in pipe Valve lip is secured to arm ti pivoted at one end thereof on a pivot member is and con-- nected the other end thereof to the movable piston rod l lo of a speed setting mot r 51. A piston 51b con to rod lilo urged upward by a spring and a variable air pressure is admitted to motor 51 above piston Mb through an inlet port 51: to vary the position of ll and sleeve valve tic in response to variations in the pressure adii used to port 55d. Motor 5i provided with a projecting stud or stop 512 which limits the upward travel of piston Slb and arm 51a to provide a minimum speed set-tins; for governor 4!. Port Elli is connected throusl'i a pipe 52 and a restricting orifice T! to the o t put chamber 53a of a speed totalizer he 1'; input chambers 53b, and a supply port 533) connected to pipe and reservoir through a pipe '54. A. spring provided between the totalizer housing and diaphragm to introduce into the totalizer a predeterm ltd biasing force opposing the input pressures in chambers 53?), 53c.

Input chamber 53?) is connected throuch a pipe 56 to the output chamber 55a of manually operable pneumatic throttle valve means 55 having a supply port 55p connected to reservoir 33 through a pipe 51. Throttle valve means is is similar in operation to totalizers 3!, 34, 53, in that the output pressure in chamber 55a is dependent upon the pressures acting against the diaphragms 55 557'. Diaphragms 551', 557' are urged to the left by a spring 55k which is compressed at variable amount by a rotatable cam 53 and a follower 59. Diaphragms 552', 557 are secured to a movable member 55m having an. exhaust port 55?" communicating with atmosphere and adapted to be variably opened by stem 551i. Movement of the diaphragms to the left closes exhaust port 551' and opens supply port 55;) to admit air to chamber 55a and pipe 56 until the pressures on diaphragms 55a, 55y are balanced, causing the diaphragms to move to the right to close the supply port 55;). Similarly, a decrease in the pressure of spring 55k causes the diaphragms to move to the right to open exhaust port 551 to exhaust pressure in chamber 55a to atmosphere until the pres sures on the diaphragms are again balanced.

Cam 58 is rotated by a throttle handle 5| operable by the engineer or operator of the turbine.

The lowest fuel position of throttle handle 6! is the idling position, during which spring 55k is compressed a predetermined amount to produce a predetermined minimum output pressure in chamber 55a The output pressure in chamber 55a increases from this predetermined minimum value as throttle handle 6! is moved from the idling position, so throttle 55 produces in output chamber a control pressure which in creases with the extent of movement of throttle handle ti from the lowest fuel position. Movement of throttle handle 6! also actuates a switch to having contacts Ella and a segment 60b. Movement of throttle handle 68 causes segment to engage contacts 56a to connect coil llla of relay 5; to a battery 62.

Input chamber of speed totalizer 53 is connectedL through a pipe to the output chamber GM of an ambient thermostatic pressure sending valve Valve to has a bimetallic element 64b secured to valve housing 64c and adapted to vary the opening of a valve member 64d controlling an exhaust port Me in response to variations in the ambient temperature. Chamber 54a is connected through a pipe 65 and pipe 5'! to reservoir 33, and variations in the position of valve member vary the area of the escape orifice of atmosphere exhaust port Me to thereby vary the pressure transmitted to chamber 530 through pipe as in response to variations in the ambient temperature.

A fuel guard totalizer 56 having an output chamber (its, a pair of input chambers 66?), 66c and a supply port 85p is provided to aid in controlling the output of fuel totalizer 3i. Input chamber 5% is connected through a pipe 61 and pipe 35 to the output chamber 34a of governor repeater totalizer and input chamber 660 is connected to pipe 35 and chamber 54a through a pipe 53 having a solenoid valve 69 therein. Valve 58 has an operating coil 69a which, when energi -ed, opens valve 69 to transmit pressure from pipe 35 to chamber 560. Supply port 6510 of totalizer 65, instead of being connected to reservoir 33, is connected throu h a pipe ll and pipe 56 to output chamber 55a of throttle valve 55, so that the pressure in output chamber 66a is limited ,y the output pressure of throttle valve 55. Output chamber Eta is connected through pipes l2, '53 to input chambers Elld, 3!), respectively, of fuel totalis' r Branch pipe M also connects chamber to opposing input chamber Ho throu h a restricting orifice l5 and a volume tank A solenoid bypass valve 49 having an operatrii. ing coil Mn is connected to pipe M to bypass orifice l upon energization of coil 49a.

The output pressure from governor repeater totalizer is transmitted throu h pipes 35 and so to fuel totalizer 3i and to the input chambers 85b, Sic, did of an excitation totalizer 81. Pipe is connected directly to input chambers Bib, 8 lo and is connected through a restricting orifice and a volume tank as to chamber 8 id. A solenoid bypass valve 5!) similar to valve 49 is connected across restricting orifice 82 to bypass this orifice upon energization of coil 58a Totalizer has a supply port tip connected to reservoir 33 through a pipe 8 5, and has an output chamber 8.1a connected through pipe 85 to the input chamber a e of a pneumatic positioner 86. Positioner 86 has a flexible diaphragm 36c connected to an arm illie forming an adjustable tap on resistor 2!. The movement of diaphragm 880 is controlled by the diirerence between the input pressure in chamber 861) and the pressure exerted by a spring 86 so that the resistance of resistor 2! is varied in response to variations in the output pressure of totalizer 8|. Arm 86c also carries a bridging member 89a adapted to close contacts 89b of a switch 89 for connecting coils 49a, 5%, 89a to a battery 9! to cause valves :9, so, 69 to open upon predetermined movement of arm 86c. A similar pneumatic positioner 81 having a diaphragm 81c and an arm tie is provided to adjust the resistance of resistor 2 2. Input chamber 81b is connected through a pipe 823 to pipe "H and the output chamber a of throttle valve 55.

The turbine is operated in two phases, during the first of which the turbine speed is held constant at a predetermined minimum value and the temperature of the motive gas supplied to the turbine is increased to increase the turbine power, When the motive gas temperature reaches a predetermined maximum value, the turbine enters the second phase of its operation during which the motive gas temperature is maintained constant at the predetermined maximum value and the turbine speed is increased to increase turbine power. The turbine is started from rest by suitable turning gear (not shown) and when the turbine becomes self-sustaining, the turbine may be loaded by movement of throttle handle 6| from the idling position.

the idling position, cam compresses spring 55k the predetermined amount to produce the predetermined minimum output pressure in chamber This output pressure is transmitted through pipe 55 to input chamber 53b of speed totalizer 53, and chambe" 530 receives a control input pressure from ambient thermostatic sender at. These pressures tend to inthe output pressure in chamber 532: to increase the speed setting of governor t i, but spring 53o introduces a predetermined biasing force into totalizer 53; opposing the pressures in chambers 530, so that the output pressure of totalizer 53 does not increase until the sum of the pressures in chambers 53b, 53c exceeds the pressure of spring 53v. Therefore, stop his maintains governor ii at its predetermined minimum speed setting.

The governor hydraulic output pressure is transmitted through pipe 3?! to chambers 361), sec of repeater totalizer where the hydraulic pressure is converted to a pneumatic output pressure in chamber The prec re from chamber Sea is transmitted through pipes 35, to input chamber sec of fuel guard totalizer 66 to control the output pressure in chanber Sta. It will be noted that the output presslre oi tctalizer is limited by the position of throttle handle E; i, since the output pressure from throttle valve 55 is supplied to supply port 665p. The output pressure from chamber is impressed on input chamber aid of the fuel totalizer 35 to control the output pressure chamber The pressure in chamber tile is transmitted through pipe as to actuator is, to cause valve 2% to supply to burner 23 the fuel required to maintain the speed of the turbine at the predetermined minimum value set by the governor. In the idling position, contacts a of switch til are not cl sed so that armature 53a and field winding E32) are not energized and motor 53 does not rotate.

When throttle handle 6! is moved from the idling position to the first traction pOSitlOll, contacts Eta close to connect armature 53c and field winding i312 to armature 52a, causing rotation of motor 93. This throttle movement also produces 7 anxincrease in tlnottl output pressure which supplies aztrs: nt e2 es in fuel signaltochamhers Sid, 93M or fuel totalizer through fuel guard totaliaer to aid the turbine in rapidly developing thehorsepower required to meet the new load. effect of this transient fuel increase is .u lly canceled by the buildup of "H6 in opposing chamber 35; through rest .a volume tank .Atthe same t' no, pressure from throttle valve is of, through pipes ll, to chamber $11) of poo to cause movement of diaphragm iil'c for decreasing amount of resistor 22 conng No. This "ature 12a to of turbine 5. Turbine :6 dcwiii below the minimum if; an underut pressure .-in c wure increase suce sively in" core 34,68, c the fuel sup plied to burn 'n r ,"F'l requirements.

The from governor arsed and t ti 2 t in fuel to burner to ie ent the turlmn .rrom falling too far'be ow tli icreased presvalue L effective to in chamber bu"dup of presneedle 1s canoe in opp o and the grad enar-ibefi c tank to call for die moves or is We.

removed ii in o o' If amount or '1 fuel totalizer fuel to 1 to :iow to burner is "'lcient to mail 1 the tin ne speed ed value under uz ierspeed t output pressure in This increased transmitted from totalizer 3 5 through ipe up 0 2. 4:, [$555 of excitation totaliz where it to decrease the pressure output eha,

govern i d theroio ssure i" oun a circuit with wi;

es the current in field no change in pipe chambe 8th, lie 81d through needle to produce a trap-- th of resistor mg the turbine to the frorzz its drawing, bridging i i-5Z7 to connect coils c tion opens --dle valves l5 and a and 1 Closure of r -g ofvalve 3% to permit air from pipe to ter input chamber throttle.

Bile. This action doubles the pressure forcing stem .5572 to open supply port so that this port is maintained :open .to permit air pressure from throttle valve 55 to go'direotly throughpipe "H, supply port .6592, output chamber 66a and throughpipe 12 totfuel totalizer iii. This results in transferring fuel controlfrom the governor to the throttle, although the governor is still operative tocontrol fuel case of extreme overspeed, 815M111], be described hereinafter. It will be understood-from the description thus far that until valve til opens, the fuel rate to burner 12-3 is controlled by :the governor rather than by the This is so because the in im output pressure from throttle valve 55 is great enough to set a fuel rate in-excess of that required to maintain the turbine at the predetermined minimum speed, so that the governorfcuts back the fuel rate by permitting only a portion of the throttle valve output pressure to pass through fuel guard 'totalizer to to fuel totalizer 36.

The above described increases in fuelraise the temperature of the motive gases in combustion chamber! and turbine 6, and as throttle handle 6! is advanced further, the temperature of the motive gas at the inlet end of the turbine reaches the maximum value to, which the turbine may be subjected. The position of throttle handle 6| at which this maximum inlet temperature is reached varies with the ambient temperaturethe maximum temperature being reached at a higher throttle position and throttle valve output'pressure when the ambient temperature is low than when the ambient'temperature is high. Thermostatic sender 64, throttle 55 and speed totalizer 53 are so designed and adjusted that the turfrom the first phase of operation to the second phase of operation when the motive gas reaches the predetermined maximum temperature, which is independent of throttle position.

When the turbine temperature reaches the predetermined maximum value, further movement of throttle handle 6| increases the output pressure of throttle valve 55 to increase the pressure chamber 531). However, this pressure increase in chamber 53b is not transmitted immediately to motor ill to increase the setting of governor 4i owing to thedelaying effect of orifice ll. This increased throttle movement also increases the pressure transmitted through pipe H to fuelguardtotalizer 66 and fuel totalizer 3| to increase the fuel supplied to burner Any increase in fuel to burner .23 will tend to increase the turbine temperature above the maximum value and thermostatic sender 28 therefore tends to increase the pressure in pipe 2'! and chamber die to decrease the fuel to burner 23. However, restricting orifice 29 and volume tank ,30 delay motor 5| is so adjusted that the governor speed setting is increased simultaneously with the increase in turbine :speed occasioned by the increased fuel and temperature, so that the governor output pressure does not change during this fuel and speed increase.

Thus, throttle valve 55 and governor 4| act jointly to vary the power delivered by the turbine in response to movement of throttle handle 6 I. Although throttle valve 55 is normally operative to control the fuel to burner 23, governor 4| may reduce the burner fuel under certain conditions. If the turbine overspeeds or when throttle handle (ii is moved to a decreased speed position, governor 4i normally increases the excitation of generator i2 to increase the turbine loading to return the speed to the desired value. However, if the governor is unable to return the turbine speed to the desired value, even when all the resistance of resistor 2i is removed from the field circuit, and the turbine continues to overspeed, the output pressure from governor 4i and governor repeater totalizer drops to zero. action reduces he pressure in input chambers 68?), ttc of the fuel guard totalizer to zero, causing closing of supply port 6611 and opening of exhaust port iifir to reduce the pressure in pipe ?2 and input chamber 31d to zero. This in turn reduces the output pressure in chamber 31a to reduce the fuel to burner 23 and thereby return the turbine to the desired speed.

Thermostatic sender 28 is operative to reduce the burner fuel if the turbine temperature tends to exceed the predetermined maximum value. Needle valve 29 and volume tank 3!! delay the transmission of changes in air pressure from sender 28 to chamber die so that sender 28 does not operate to limit the opening of fuel valve 24 during transient increases in the temperature of the turbine motive gas above the predetermined maximum value, such as are encountered during acceleration and deceleration of the turbine.

To reverse the locomotive, any suitable known means may be provided to reverse the direction of current iiow in field winding l3?) with respect to its direction for forward movement, so that motor armature i do rotates in the opposite direction. The remainder of the operation of the system for reverse movement of the locomotive is the same as that described above for forward movement.

Although but one embodiment has been illustrated and described, it will be apparent to those skilled in the art that various changes and modifications may be made therein without departing from the spirit of the invention or from the scope of the appended claims. Features disclosed but not claimed herein are claimed in application of Stanley W. James, Serial Number 240,013, filed August 2, 1951, now Patent Number 2,636,139, issued April 21, 1953.

It is claimed and desired to secure by Letters Patent:

1. In a control system for a combustion chamber supplying motive gas to a gas turbine, the combination of a source of air under pressure, a fuel regulating valve, operating means for said valve connectable with said source to cause said valve to be variably opened for controlling the flow of fuel to said chamber, a pneumatic totalizing device having an input chamber, an output chamber and a supply port communicating with said output chamber, said input chamber being adapted to receive a control pressure for controlling the pressure transmitted from said supply port to said output chamber, regulating means including an adjustable governor and a second iii pneumatic totalizing device for producing a first control pressure dependent upon the speed of said turbine, a manually operable throttle connected to said source for producing a second control pressure which increases with the extent of movement of said throttle from the cutoff position, means connecting said regulating means to said input chamber to impress said first control pressure thereon, means connecting said throttle to said supply port to impress said second control pressure thereon, and means connecting said output chamber to said fuel valve operating means to control the opening of said valve in response to variations in the pressure in said output chamber, whereby said fuel valve is adjusted by said governor to a variable position within a range extending from closed position to a limit position which varies with the position of said throttle independently of the action of said governor.

2. In a control system for a combustion chamber supplying motive gas to a gas turbine, the combination of a source of air under pressure, a fuel regulating valve, operating means for said valve connectable with said source to cause said valve to be variably opened by air from said source for controlling the flow of fuel to said chamber, a first pneumatic totalizing device having an input chamber, an output chamber and a supply port communicating with said output chamber, said input chamber being adapted to receive a control pressure for controlling the pressure transmitted from said supply port to said output chamber, an adjustable governor for producing a hydraulic pressure dependent upon the speed of said turbine, a second pneumatic totalizing device connected to said source for converting said hydraulic pressure to a first pneumatic control pressure, a manually operable throttle connected to said source for producing a second control pressure which increases with the extent of movement of said, throttle from the cutoff position, means connecting said second totalizing device to said input chamber to impress said first control pressure thereon, means connecting said throttle to said supply port to impress said second control pressure thereon, and means connecting said output chamber to said fuel valve operating'means to control the opening of said valve in response to variations in the pressure in said output chamber, whereby said fuel valve is adjusted by said governor to a variable position within a range extending from closed position to a limit position which varies with the position of said throttle independently of the action of said governor.

3. In a control system for a combustion chamber supplying motive gas to a gas turbine driving an electric generator, the combination of a source of air under pressure, a fuel regulating valve, operating means for said valve connectable with said source to cause said valve to be variably opened by air from said source for controlling the flow of fuel to said chamber, a pneumatic totalizing device having an input chamber, an output chamber and a supply port communicating with said output chamber, said input chamber being adapted to receive a control pressure for controlling the pressure transmitted from said supply port to said output chamber, regulating means including an adjustable governor and a second pneumatic totalizing device for producing a first control pressure dependent upon the speed of said turbine, a manually operable throttle connected to said source for producing a l 1 second control pressure which increases with the extent of movement of said throttle from the out off position, means connecting said regulating means to said input chamber to impress said first control pressure thereon, adjustable resistance means for controlling the excitation of said generator, pneumatic means for controlling the resistance of said resistance means, means connecting said throttle to said pneumatic means to vary the loading of said turbine in response to variations in said second control pressure, means connecting said throttle to said supply port to impress said second control pressure thereon, and means connecting said output chamber to said fuel valve operating means to control the opening of said valve in response to variations in the pressure in said output chamber, whereby said fuel valve is adjusted by said governor to a variable position within a range extending from closed position to a limit position which varies with the the position of said throttle independently of the action of said governor.

4. In a control system for a combustion chamber supplying motive gas to a gas turbine, the

combination of a source of air under pressure,

a fuel regulating valve, operating means for said valve connectable with said source to cause said valve to be variably opened by air from said source for controlling the how of fuel to said chamber, a first pneumatic totalizing device having an input chamber, an output chamber and a supply port communicating with said output chamber, said input chamber being adapted to receive a control pressure for controlling the pressure transmitted from said supply port to said output chamber, regulating means including an adjustable governor and a second pneumatic totalizing device for producing a first control pressure dependent upon the speed of said turbine, a manually operable throttle connected to said source for producing a second control pres-- sure which increases with the extent of movcment of said throttle from the cutoff position, means connecting said regulating means to input chamber to impress said first control pressure thereon, means connecting said throttle to said supply port to impress said second control pressure thereon, a third pneumatic totalizing device connected to said source for controlling the opening of said valve, and means connecting said output chamber to said third totalizing device to control the opening of said valve in response to variations in the pressure in said output chamber, whereby said fuel valve is adjusted by said governor to a variable position within a range extending from closed position to a limit position which varies with the position of s, throttle independently of the action of said governor.

5. In a control system for a combustion chamber supplying motive gas to a gas turbine driv an electric generator, the combination of a source of air under pressure, a fuel regulating valve, operating means for said valve connectable to said source to cause said valve to be variably opened by air from said source for controlling the fioW of fuel to said chamber, a pneumatic totalizing device having an input chamber, an output chamber and a supply port communicat-- ing with said output chamber, said input chamber being adapted to receive a control pressure for controlling the pressure transmitted from. said supply port to said output chamber, regulating means including an adjustable governor and a second pneumatic totalizing device for producing a first control pressure dependent upon the speed of said turbine, said first control pressure decreasing when said turbine speed increases, a manually operable throttle connected to said source for producing a second control pressure which increases with the extent of movement of said throttle from the cutoff position to set a desired turbine speed, adjustable resistance means for varying the excitation of said generator, pneumatic means for varying the resistance of said resistance means, a third pneumatic totalizing device, means connecting said pneumatic means to said third pneumatic totalizing device, means for impressing said first control pressure on said third pneumatic totalizing device. for varying the loading of said turbine in response to variations in said first control pressure, means connecting said regulating means to said input chamber to impress said first control pressure thereon, means connecting said throttle to said supply port to impress said second control pressure thereon, and means connecting said output chamber to said fuel valve operating means to control the opening of said valve in response to variations in the pressure in said output chamber, whereby said governor is operative to decrease said first control pressure for reducing the opening of said fuel valve if the adjustment of said resistance means produces insufiicient loading of said turbine to maintain said turbine at the set speed.

6. In a control system for a combustion chamber supplying motive gas to a gas turbine driving an electric generator, the combination of a source of air under pressure, a fuel regulating valve, operating means for said valve connectable to said source to cause said valve to be variably opened by air from said source for controlling the flow of fuel to said chamber, a first pneumatic totalizing device having an input chamber, an output chamber and a supply port communicating with said output chamber, said input chamber being adapted to receive a control pressure for controlling the pressure transmitted from said supply port to said output chamber, an adjustable governor for producing a hydraulic pressure dependent upon the speed of said turbine, said hydraulic pressure decreasing when said turbine speed increases, a second pneumatic totalizing device connected to said source and to said governor for converting said hydraulic pressure to a first pneumatic control pressure, a manually operable throttle connected to said source for producing a second control pressure which increases with the extent of movement of said throttle from the cutoff position to set a desired turbine speed, adjustable resistance means for varying the excitation of said generator, pneumatic means for varying the resistance of said resistance means, a third pneumatic totalizing device, means connecting said pneumatic means to said third pneumatic totalizing device, means for impressing said first control pressure on said third pneumatic totalizing device for varying the loading of said turbine in response to, variations in said first control pressure, means connecting said second pneumatic totalizing device to said input chamber to impress said first control pressure thereon, means connecting said throttle to said supply port to impress said second control pressure thereon, and means connecting said output chamber to said fuel valve operating means to control the opening of said valve in response to variations in the pressure in said output chamber, whereby said governor is operative to decrease said first control pressure for reducing the opening of said fuel valve if the adjustment of said resistance means produces insufficient load ing of said turbine to maintain said turbine at the set speed.

7 In a control system for a combustion chamber supplying motive gas to a gas turbine driving an electric generator, the combination of a source of air under pressure, a fuel regulating valve, operating means for said valve connectable to said source to cause said valve to be variably opened by air from said source for controlling the flow of fuel to said chamber, a pneumatic totalizing device having an input chamber, an output chamber and a supply port communicating with said output chamber, said input chamher being adapted to receive a control pressure for controlling the pressure transmitted from said supply port to said output chamber, means including an adjustable governor and a second pneumatic totalizing device for producing a first control pressure dependent upon the speed of said turbine, said first control pressure decreasing when said turbine speed increases, a manually operable throttle connected to said source for producing a second control pressure which increases with the extent of movement of said throttle from the cutofi position to set a desired turbine speed, adjustable resistance means for varying the exicitation of said generator, pneumatic means for varying the resistance of said resistance means, a third pneumatic totalizing device, means connecting said pneumatic means to said third pneumatic totalizing device, means for impressing said first control pressure on said third pneumatic totalizing device for varying the loading of said turbine in response to variations in said first control pressure, means connecting said second pneumatic totalizing device to said input chamber to impress said first control pressure thereon, means connecting said throttle to said supply port to impress said second control pressure thereon, a fourth pneumatic totalizing device connected to said source and to said output chamber, and means connecting said fourth pneumatic totalizing device to said fuel valve operating means to control the opening of said valve in response to variations in the pressure in said output chamber, whereby said governor operative to decrease said first control pressure for reducing the opening of said valve if the adjustment of said resistance means produces insufficient loading of said turbine to maintain said turbine at the set speed.

HAROLD E. REICHERT.

References Cited in the file of this patent UNITED STATES PATENTS James Apr. 21, 1953 

